Pulpwood-debarking drum having angularly slotted wall and stationary shearing bars



July 5, 1960 A. s. WAKEMAN PULPWOOD-DEBARKING DRUM HAVING ANGULARLYSLOTTED WALL AND STATIONARY SHEARING BARS 3 Sheets-Sheet. 1

Filed Aug. 24. 1956 INVENTOR. W

y 1960 A. G. WAKEMAN 2,943,656

PULPWOOD-DEBARKING DRUM HAVING ANGULARLY SLOTTED WALL AND STATIONARYSHEARING BARS Filed Aug. 24, 1956 3 Sheets-Sheet 2 & Z/NVEN TOR.

July 5, 1960 A. G; WAKEMAN 2,943,656

PULPWOOD-DEBARKING DRUM HAVING ANGULARLY SLO'IITED WALL AND STATIONARYSHEARING BARS 3 Sheets-Sheet 3 Filed Aug. 24, 1956 INVEN TOR.

nited States The present invention relates generally 'to the preparationof wood for pulping and, more particularly, relates to an apparatus andmethod for removingbark'from the slabs and edgings which result fromsawmill operation so as to make these hitherto waste materialsavailablefor making various cellulosic products.

In various parts of the country there is a large amount of saw-millwaste which is useful only as fuel because it is in odd shapes andsizes. 7 Typical of this material are the so-called slabs which are cutfrom the sides or logs so as to provide a relatively flat-surfacedtimber for use in the sawmill. Th'o'se slabs are generally arcuat'e incross section, the curved side being covered with bark. Other wastematerial of this type are the so-called edgings which are cut from theedges of the rough boards in the initial sawmill operation. Theseedgings are also'covered with bark on one side.

Attempts have been made to employ slabs an'dedgings in paper-makingoperations but it has been very difficult to effect the removal of barkfrom the slabs so that clean, bark-free wood is available for thepulping operation. Economically, it is impossible to remove the barkfrom the slabs and edgings on a piece-by-piece basis because of themanual labor and the expense involved. On the other hand, attempts havebeen made to pass the slabs and edgings through ordinary barkingequipment which is designed for the handling of pulpwood, i.e., lengthsof wood 46 feet in lengths which are generally circular in crosssection, but these attempts have met with failure. H

The usual barking equipment for ordinary pulpwood consists of a largeelongated drum which may be from about to 12 feet in diameter and whichmay be from about 30 to 65 feet in length. These drums are made in theform of a cylinder which includes on the inner periphery thereof aseries of circumferentially spaced, longitudinally extending bars havingopenings therebetween for permitting the bark to leave the drum. Theseopenings are from about 2-4 inches wide and extend longitudinally of thedrum. The pulpwood is fed into this drum which is rotated so that thepieces of wood rub upon one another and upon the bars so as to effectthe removal of the bark, the bark passing out through the openingsbetween the bars.

When slabs or edgings are put in such a barking drum, severaldifficulties manifest themselves. First, the edges of the individualpieces become wedged into the spaces between the longitudinal bars so asto jam the barkremoval openings. Second, the wedged pieces and the freepieces become so interentangled that there is a poor barking action andthe load in the barking drum does not feed through the drum. Andfinally, in such an operation, the slabs and edgings are so broken upthat they are of little use for paper-making operations since a greatpercentage of the wood is splintered and passes out of the drum with thebark toth'e'bark pile.

Accordingly, it the principal object of the invention to provide anapparatus and a method for elfecting the atent lQQ 2 removal of barkfrom sawmill waste such as slabs and edgings in an fefiicien't andeconomical manner. Other objects and "advantages of the invention willbecome known by reference to the appended drawings andthe followingdescription of apparatus embodying the invention.

I Fig. l is a side elevation of a barking drum embodying various of thefeatures of the invention;

Fig. 2 is an enlarged perspective view ofa section of the externalsurface of the drum shown in Fig.1;

Fig. 3 is a-verticah transverse sectional viewtaken on line 3-3 in Fig.l, a stationary partition at the end of the drum beingomitted;

Fig. 4 is an enlarged-scale, fragmentary, vertical, ,longitudinal,sectional view taken on line 44 in Fig. 3;

Fig. 5 is a vertical, transverse sectional view of a modified barkingdrum embodying features of the invention;

'Fig. 6 is a fragmentary, longitudinal sectional view taken on line 6'6in Fig. 5; and v Fig. 7 is a fragmentary perspective view of a sectionof the modified barking drum shown in Figs. Sand 6.

In the drawings there are illustrated two embodiments of the inventionwhich are adapted to be employed with slabs or edgings. The embodimentillustrated in Figs. 1 to 4, inclusive, includes generally a frame 1 1,a generally horizontally disposed barking drum 13, means 15 forsupporting the barking drum for rotation about its longitudinal axis,means 17 for effecting the rotation of said drum, and shearing means 19for severing and freeing any splinters or sticks which might becomewedged in the barking drum 13; Of course, conveying means 21 areprovided for feeding the slabs and edgings to the barking drum 13 aswell as discharge conveying means 23 for carrying away the barked woodand a discharge conveyor means, 25 for .carrying away thebark which isremoved from the wood. The embodiment illustrated in Figs. 5 to 7inclusive, preferably includes the'features of the embodiment shown inFigs. l to 4 and, in-ad'dition, includes means 26 for preventing theslabs or edgings from becoming interentangled, thus insuring that eachpiece of wood is uniformly tumbled and subjected to barkingaction. H I v7 The frame 11 in the illustrated structure is generally box-like and isfabricated from a number of structural members. The frame 1-1 includes anumber of vertically extending support members 27 which are set in asuitable foundation 2% at their lower ends andwhose upper ends are,connected by a series of horizontally disposed longitudinal members 31and transverse members 33 which provide a supporting platform for thesupport means 15 for the drum 13 and for the drum-rotating means 17. Asecond set of horizontally disposed transverse members 33a are providedbetween the vertical members 27 adjacent the lower ends thereof so as toreinforce thestructure and to provide a support means for the shearingmeans 19 which is adapted to act in co-operation with the barking drum13. p

In the illustrated structure, the barking drum 13 comprises an elongatedcylindrical shell 34 which may be fabricated from sheet steelor thelike. In the interior of the shell there are provided a plurality ofmembers 35 arranged around the periphery thereof which are alignedlongitudinally of the shell and which are rigidly attached thereto.

The members 35 serve to reinforce the shell 34 and to provideprojections for causing enough frictional force between the shell 34 andthe slabs of wood being barked so that the slabs are carried with theshell as it rotates. The slabs finally fall back to the lower portion ofthe shell, the alternate lifting and falling action thus providedeffecting the removal of the bark from the slabs. In the illustratedstructure, the members 35 are fabricated from angle-iron structuralmembers but various other shapes may be successfully employed as in thecase of barking drums for pulpwood in standard sizes. In the illustratedstructure, eight of the members 35 are employed but more or fewer may beemployed without materially affecting the efficiency of the operation.

In order that the bark which is removed from the slabs may be removedfrom the interior of the shell 34 there are provided a number of narrowelongated slots 36 which are arranged generally longitudinally of theaxis of the shell and preferably which are inclined relative to the axisof the shell. In the illustrated embodiment, the slots 36 are inclinedrelative to the axis of the shell 36 at an angle of about 15 (the angleon in Fig. 1), however, the exact angle'is not of particular importance.

The slots 36 desirably are wide enough to permit the stripped-off barkparticles to pass therethrough but narrow enough so that sticks andlarge splinters which interfere with the free movement of materialcannot become wedged therein. The preferred width has been found to bebetween about if; and inches, but wider and narrower widths may also beemployed. The length of the slots 36 is not of great importance,however, it should be borne in mind that the length should be maintainedwithin limits which will provide a strong shell structure.

As illustrated in the drawings, the drum 13 is supported for rotation inthe frame 11 by the supporting means 15. The drum 13 may be supported inany suitable way as, for example, by mounting it on a set of trunnions.However, in the illustrated structure, the drum 13 is supported upon aseries of sets of support chains and sprockets so as to more readilyabsorb stresses in the drum 13 due to the variations in load which occurunder different working conditions.

Specifically, in the illustrated unit the drum is supported on the lowerruns of four endless chains 37 which are longitudinally spaced along thedmm 13. Each of the chains 37 is supported on its upper run by means ofa pair of sprockets 39 and 39a. Each of the sprockets 39 is rotatablysupported on a longitudinally extending shaft 41 which is journaled forrotation in suitable bearings 43 (Fig. 3) which are supported on theupper transverse frame members 33. The sprockets 39 are adapted torotate independently of the shaft 41 which, as will be hereinafterdescribed, is employed as the drive shaft for the drum 13. Each of thesprockets 39w is supported in a slidable bearing 45 which is preferablyspring biased as illustrated at 47 in Fig. 3 so as to maintain tensionon its associated chain 37.

The chains 37 are each adapted to engage a sprocket ring 49 (Fig. 2)which is attached to and which extends around the circumference of theshell 34 in the plane of the sprockets 39 and 39a. Thus, the drum iscradled in the four chains 37 and is free to rotate. Longitudinalmovement of the drum 13 as it is rotated is minimized by the chains 37,however, in order to effectively prevent both sidewise movement of thedrum as well as longitudinal movement, a pair of guide rollers 51 arejournaled on flanges 52 rigidly attached to the upright frame member 27at each end of the unit. Each pair of rollers 51 rides in a flangedguide ring 53 (Fig. 2) which is attached to, and which extendscircumferentially around, the outer surface of the shell so as to form atrackway for the guide rollers 51. The engagement of each pair of therollers 51 in the channel provided by the associated guide ring 53prevents sidewise movement of the drum 13 as it is rotated as well aslongitudinal movement. However, this engagement does not preventvertical movement of the drum incident to the stresses of operation.

The means for effecting rotation of the barking drum 13 in theillustrated structure includes a pair of drive chains 55, one of whichis arranged at each end of the drum 13. The drive chains 55 each engagea sprocket ring 57 which extends around and which is attached to theouter surface of the drum 34. Each of the sprocket rings 57 on the drum13 is operatively connected by the chain 55 to a sprocket 59 (Fig. 1)which is keyed to the shaft 41.

Rotation of the shaft 41 is effected by a driving connection with asuitable motor such as the electric motor 61 which is supported on theframe 11. The driving connection includes a drive belt 63 whichinterconnects a pulley 65 on the motor shaft with a pulley 67 on acountershaft 69. The countershaft 69 is journaled for rotation insuitable bearings 71 on the frame 11 and this countershaft is connectedto the shaft 41 by a pair of speed-reducing gears 73 and 73a, keyedrespectively to the shafts 69 and 41. The exact manner of rotating thedrum is not important to the attainment of the objects of the inventionand any suitable drive means which can accomplish the desired rotationof the drum is satisfactory.

As has been previously pointed out, a shearing means 19 is provided toco-operate with the drum 13 so as to sever any sticks or splinters whichmight become wedged in the slots 36 thereby causing the slabs to becomejammed or entangled. The shearing means 19 includes a shearing bar 77and a suitable mounting arrangement therefor. In the illustratedstructure the mounting arrangement comprises a longitudinally extendingmounting bar 75 (Figs. 3 and 4) which is rigidly connected to thetransverse frame member 33a. The mounting bar 75 may convenientlycomprise an angle-iron structural member, as illustrated.

As illustrated, the shearing bar 77 is mounted on the longitudinallyextending mounting bar 75. The shearing bar 77 in the illustratedembodiment comprises a series of angle sections 77a (Fig. 4) which aresuitably attached to the mounting bar 75 by a series of bolts 79 or thelike. As shown, particularly in Fig. 4, the reason for providing theshearing bar 77 in the illustrated structure as a series of short barsrather than one long bar is the necessity of permitting the sprocketrings 49 and 57 and the chain 37 to pass therethrough. In the event thatthe drum 13 is mounted for rotation on trunnions, the shearing bar, ofcourse, could be a single continuous length.

While various forms of shearing bars 77 may be employed, it has beenfound desirable to provide a shearing bar which is fabricated from anangle structural member which has the horizontal leg of the angleextending from the leading side of the vertical leg, considering thedirection of relative movement of the shearing bar drum 13 as theyapproach one another. As shown in the drawings (Fig. 3) the drum rotatesin the direction of the arrow 81 and the horizontal leg of the angle bar77 extends to the right in that figure. As illustrated, the leading edgeof the horizontal leg of the angle bar 77a may be sharpened to provide acutting edge so as to facilitate cutting off any sticks or splinterswhich might protrude through and wedge in the slots 36. In the eventthat metal or the like becomes wedged in the slots 36, the drum is freeto move upwardly against the weight of the drum so that the object maypass between the bar 77 21nd the drum 13 so as to minimize damage to thedrum As has been pointed out, conveying means 21 are provided forconveying the slabs and edgings to the barking drum 13. The means 21 inthe illustrated structure includes a belt conveyor 83 which dischargesthe slabs onto a chute 85 which is preferably arranged at an angle ofbetween 30 and 60 to the horizontal. The chute 85 in addition to aninclined bottom surface 86 includes a pair of side walls 87 as shown inFigs. 1 and 3. The side walls illustrated are arranged to converge sothat the appease slabs fall into the barking drum in'an aligned arrange'ment.

13. The belt conveyor 91 discharges onto aconve'yor 93 which carries thebark to a disposal point. In order to insure that the bark falls ontothe belt 91, a pair of sloping aprons 95 are provided, one on eachsideo'f the belt 91 so as to direct the bark particles onto the belt.The aprons 95 are mounted on the frame 11 in any suitable fashion andare of the type ordinarily employed in commercial barking equipment.

Discharge of the barked slabs is effected by the conveyor means 23 whichincludes a chute 97 positioned at the discharge end of the barking drum13. In order to cause the barked slabs to pass down the chute 7, astationary partition 99 is provided to maintain a level of slabs in thedrum while it is being rotated. Again, the spacing between the partition99 and the discharge end of the barking drum 13 is such that the barkedslabs will not fall therebetween. From the chute 9'7 the barked slabspass onto a belt conveyor 101 which carries them to their point ofultimate use.

In operation, the drum 13 is rotated by the motor'61 through the drivingconnections which have been described. The slabs to be barked are fedonto the chute 85 whereupon they slide into the drum 13 in asubstantially aligned relationship. As the drum is rotated it graduallyfills with slabs to approximately /3 to /2 of its diameter and, as theslabs move towards the outlet end, the frictional forces occasioned bythe slabs rubbing one upon the other due to the. rotation of the drum'13 which causes the slabs to tumble inside of the drum, effects theremoval of the bark. The pulverized bark particles fall through theslots 36 onto the bark conveyor 25 which carries the bark to a disposalpoint. The slabs, after the bark has been removed, move out the outletend down the chute 97 to the conveyor 101 which carries them to thepoint of utilization.

It has been found that various of the features of'the apparatus whichhave been described co-operate to produce an excellent barking actionwith'a minimum of damage to the slabs being handled.

One feature which'contributes to eificient operation is the arrangementof the slots 36 at an angle to the axis of the drum. It has been foundthat when the slots are arranged at an angle as illustrated thesplinters and chunks do not become as readily wedged into the slots andthe bark particles discharge more readily through the slots than in thecase of slots which are parallel to the axis of the drum. The width ofthe slots also contributes to efficient operation and it has been foundthat slots from to /2 of an inch are desirable but somewhat wider ornarrower slots may be employed.

Another feature of the barking drum which contributes to its efficientoperation is the shearing. means 19 which on each revolution of the drumcuts off any sticks or splinters which may protrude through the slots36. This insures that the slots remain open since it has been found thatafter the protruding end is cut ofi, movement of the load in the drumpulls the remaining portion ofthe wedged piece into the interior of thedrum thereby clearing the slot.

In operating a barking drum of the type described on 1 slabs, it hasbeen found that the length of the slabs being handled should be betweenabout A to /6 of the diameter of the drum. Thus ithas been founddesirable to employ a drum' having a diameter of from 8 to 12 feet forslabs which have been cut to a length of 2 feet. This promotes moreeflicient barking action and results in faster barking.

The rate of rotation of the drum also may 'aid in obt'ainingawell-barked product and it has been found that {the desirable speed ofrotation is about 10 rpm. The s'peed-"of -rota-tion, however, dependsupon the amount of or edgings from becoming interentangled and thusassures that each piece of slabs or edging is subjected to a uniformtumbling and barking action.

The means 26 illustrated in the drawings comprises the provision of aseries of elongated baffie or strut members 103 which are interlaced inthe interior of the barking drum so as to break apart any interentangledmasses of Wood. The baffle members 103 may be structural-steel memberssuch as angle iron or the like which can be bolted or otherwise fastenedin place and which will act upon the slabs or edgings as they movethrough the drum. Preferably, however, the baffle members 103 areflexible so as to reduce fatigue failure in the members and to alsoprovide for a slight swinging or yielding action as the members aremoved through the mass of wood in the barking drum. Suitable flexiblemembersare link chains, cables or the like, or combinations of shortchains or cable sections with short rigid sections to provide a memherwhich is relatively flexible. The most economical and satisfactorybafi'le members are chains and, accordingly, in the illustratedstructure (Figs. 57) the members 103 comprise a plurality of chains. Themembers 103 maybe arranged in either a regular or haphazard patternwithin the drum.

The bafile members 103 which are chains, may be arranged in a patternsuch as shown in the drawings. In this pattern the members 103 aredisposed so as to divide the drum into four segments, the members beingstretched transversely across the drum 34 and longitudinally along thelengthof the drum so as to provide a combined crossed and zigzagpattern. Only one typical longitudinal section of the drum 34 isillustrated in Figs. 5-7 and this section shows only one of a series ofcoplanar chains 103a, each of which extends across the drum axis from abracket 105, the latter being one of a longitudinal row of bracketsattached to the inside wall of the drum, to a bracket 10511, which isone of an opposite row of brackets and which is longitudinally spacedtoward the outfeed end of the drum, from the point of attachment of thebracket 105.

Another series of coplanar chains 103b, the common plane of whichperpendicularly intersects the common plane of the chains 103a, aremounted inside the drum and are stretched across the drum axis, one ofthese chains 103!) being shown in Figs. 6 and 7 as extending betweenbrackets 107 and 107a, which are-elements of two opposite rows ofbrackets, the point of attachment of the bracket 107a beinglongitudinally spaced, toward the infeed end of the drum, from the pointof attachment of the bracket 107. Other chains 103a extend across thedrum axis, but are stretched between the brackets 155 and those brackets105a on the opposite wall which are spaced, from the brackets 105,toward the infe'ed end of the drum, whereby the chains 103a and 1030form a zigzag pattern lengthwise of the drum. Still other chains 103dconnect the brackets 107 with those brackets 107a on the opposite'wallwhich are longitudinally-spaced, to-

ward the outfeed end of the drum, from the brackets 107, so as to form asecond zigzag pattern of chains lengthwise of the drum. Thus, eachzigzag pattern comprises a series of coplanar chains, and the twopatterns define perpendicular planes that intersect each other along thedrum axis. The arrangement which has been described involves a regularpattern. However, the advantages of the invention are equally wellsecured with a haphazard pattern of chains or baffling means within theinterior of the drum.

The bafile members 103 may be located throughout the length of the drum34 or they may be located only in the regions where the wood becomesinterentangled to such an extent that it does not effectively rub offthe bark surfaces of the pieces being barked. In operation, it has beenfound that the provision of the members 103 greatly enhances the barkingeificiency of a barking drum and at the same time does not undulyincrease splintering of the wood being barked.

In the foregoing there has been described an improved apparatus forbarking slabs and edgings, which have hitherto been waste material, soas to make them available for use as pulpwood. As has been pointed out,the various features of the apparatus co-operate to provide an efficientmeans for accomplishing the barking of this class of materials which hasnot been possible with the prior art machines.

Various features of the invention are set forth in the appended claims.

I claim:

1. In an apparatus of the class described adapted for use in barkingslabs of the wood, an elongated cylindrical shell having an inlet at oneend for bark-bearing wood and an outlet at the other end thereof forbarked wood, said shell having a plurality of circumferentially spaced,narrow, elongated, generally longitudinally extending openings in thesunface of said cylinder through which bark may pass outwardly from theinterior of said cylinder, said openings having a width of from about to/2 inch, and means for rotating said shell about its longitudinal axis.

2. In an apparatus of the class described adapted for use in barkingslabs of wood, an elongated cylindrical shell having an inlet at one endfor bark-bearing wood and an outlet at the other end thereof for barkedwood, said shell having a plurality of circumferentially spaced, narrow,elongated openings in the surface of said cylinder through which barkmay pass outwardly from the interior of said cylinder, said openingsbeing arranged at an angle of about 15 relative to the longitudinal axisof said shell, and means for rotating said shell about its longitudinalaxis.

3. In an apparatus of the class described adapted for use in barkingslabs of wood, an elongated cylindrical shell having an inlet at one endfor bark-bearing wood and an outlet at the other end thereof for barkedwood, said shell having a plurality of circumferentially spaced,elongated openings in the surface of said cylinder through which barkmay pass outwardly from the interior of said cylinder, said openingshaving a width of from about to /2 inch, said openings being arranged atan angle to the longitudinal axis of said shell, and means for rotatingsaid shell about its longitudinal axis.

4. In an apparatus of the class described adapted for use in barkingslabs of wood, an elongated cylindrical shell having an inlet at one endfor bark-bearing wood and an outlet at the other end thereof for barkedwood, said shell having a plurality of circumferentially spaced, narrow,elongated, generally longitudinally extending openings in the surface ofsaid cylinder through which bark may pass outwardly from the interior ofsaid cylinder, means for rotating said shell about its longitudinalaxis, and stationary means extending along the outer surface of saidcylinder in the region of said openings,

. said stationary means overlying the entire longitudinal extent of thepath traveled by each of said openings and extending in close proximityto said openings for shearing-ofi any material which extends throughsaid openings.

5. In an apparatus of the class described adapted for use in barkingslabs of wood, an elongated cylindrical shell having an inlet at one endfor bark-bearing wood and an outlet at the other end thereof for barkedwood, said shell having a plurality of circumferentially spaced, narrow,elongated, generally longitudinally extending openings in the surface ofsaid cylinder through which bark may pass outwardly from the interior ofsaid cylinder, means for rotating said shell about its longitudinalaxis, and a bar disposed in close proximity to the outer surface of saidshell and generally parallel to the longitudinal axis thereof, said barextending across the path traveled by each of said openings, and astationary support for said bar, said bar being effective to shear-offany material which extends through said openings incident to therotation of said shell.

6. In an apparatus of the class described adapted for use in barkingslabs of wood, an elongated cylindrical shell having an inlet at one endfor bark-bearing wood and an outlet at the other end thereof for barkedwood, said shell having a diameter of between about 4 and 6 times thelength of slabs of wood being barked and being provided with a series ofcircumferentially spaced, narrow, elongated openings therein throughwhich bark may pass outwardly from the interior of said cylinder, saidopenings being arranged at an angle relative to the longitudinal axis ofsaid shell, the interior of said shell being provided with a pluralityof longitudinally extending members which are attached thereto, saidmembers being adapted to engage slabs of wood being debarked and to aidin imparting a tumbling action thereto, means for rotating said shellabout its longitudinal axis, and stationary means extending along theouter surface of said cylinder in the region of said openings and inclose proximity thereto for shearing off any material which extendsthrough said openings.

7. In an apparatus of the class described adapted for use in barkingslabs of wood, an elongated cylindrical shell having an inlet at one endfor bark-bearing wood and an outlet at the other end thereof for barkedwood, said shell having a diameter of between about 4 and 6 times thelength of slabs being barked and being provided with a series ofcircumferentially spaced, narrow, elongated openings therein throughwhich bark may pass outwardly from the interior of said cylinder, saidopenings being arranged at an angle relative to the longitudinal axis ofsaid shell and having a width of from about /3 to /2 inch, the interiorof said shell being provided with a plurality of longitudinallyextending members which are attached thereto, said members being adaptedto engage slabs of wood being barked and to aid in imparting a tumblingaction thereto, means for rotating said shell about its longitudinalaxis, and stationary means extending along the outer surface of saidcylinder in the region of said openings and in close proximity theretofor shearing off any material which extends through said openings.

8. In an apparatus of the class described adapted for use in barkingslabs of wood, an elongated cylindrical shell having an inlet at one endfor bark-bearing wood and an outlet at the other end thereof for barkedwood, said shell having a plurality of circumferentially spaced openingsin the surface thereof through which bark may pass outwardly from theinterior of said shell, the interior of said shell being interlaced witha plurality of chains which are stretched across the interior of saidshell and which are adapted to break apart interentangled pieces of woodbeing barked, said chains being positioned in such manner that they aredirected transversely as well as longitudinally of the interior of saidshell, and means for rotating said shell about its longitudinal axis.

9. In an apparatus of the class described adapted for use in barkingslabs of wood, an elongated cylindrical shell having an inlet at one endfor bark-bearing wood and an outlet at the other end thereof for barkedwood, said shell having a plurality of circumferentially spaced openingsin the surface thereof through which bark may pass outwardly from theinterior of said shell, the interior of said shell being interlaced witha plurality of chains which are spaced longitudinally of the drum andstretched across the interior of said shell in crossed and zigzagarrangement and which are adapted to break apart interentangled piecesof wood being barked, and means for rotating said shell about itslongitudinal axis.

10. In an apparatus of the class described adapted for use in barkingslabs of wood, an elongated cylindrical shell having an inlet at one endfor bark bearing wood and an outlet at the other end thereof for barkedwood, said shell having a plurality of circumterentially spaced,elongated openings in the surface of said cylinder through which barkmay pass outwardly from the interior of said cylinder, said openingshaving a width of from about to inch, said openings being arranged at anangle to the longitudinal axis of said shell, the interior of said shellbeing interlaced with a plurality of flexible, elongated biafile memberswhich are attached at each end to the interior of said shell and whichare adapted to break apart inter-entangled pieces of wood being barked,and means for rotating said shell about its longitudinal axis.

11. In an apparatus or the class described adapted for use in barkingslabs of Wood, an elongated cylindrical shell having an inlet at one endfor bark-bearing wood and an outlet at the other end thereof for barkedwood, said shell having a plurality of circumferentially spaced, narrow,elongated, generally longitudinally extending openings in the surface ofsaid cylinder through which mark may pass outwardly from the interior ofsaid cylinder, the interior of said shell being interlaced with aplurality of flexible, elongated bafile members which are attached ateach end to the shell and are adapted to break apart interentangledpieces of the 'wood being barked, means for rotating said shell aboutits longitudinal axis, and a stationary bar disposed in close proximityto the outer surtace of said shell, said bar overlying the entirelongitudinal extent of the path traveled by each of said openings, and astationary support for said bar, said bar being effective to shear-offany material which extends through said openings incident to therotation out said shell.

12. In an apparatus of the class described adapted iior use in barkingslabs of wood, an elongated cylindrical shell having an inlet at one endtor bark-bearing wood and an outlet at the other end thereof for barkedwood, said shell having a plurality of circumterentially spaced, narrow,elongated, generally longitudinally extending openings in the surface ofsaid cylinder through which bark may pass outwardly from the interior ofsaid cylinder, the interior of said shell being interlaced with aplurality of chains which are attached at each end to the interior ofsaid shell and which are adapted to break apart interenltangled piecesof the wood being barked, means for rotating said shell about itslongitudinal axis, and a stationary bar disposed in close proximity tothe outer surface of said shell, said bar overlying the entirelongitudinal extent of the path traveled by each of said openings, and astationary support for said bar, said bar being effective to shear-offany material which extends through said openings incident to therotation of said shell.

13. In an apparatus of the class described adapted for use in barkingslabs of wood, an elongated cylindrical shell having an inlet at one endfor bark-bearing wood and an outlet at the other end thereof for barkedwood, said shell having a diameter of between about 4 and 6 times thelength of slabs of wood being barked and being provided with a series ofciroumterentially spaced, narrow, elongated openings therein throughwhich bark may pass outwardly from the interior of said cylinder, saidopenings being arranged at an angle relative to the longitudinal axis ofsaid shell, the interior of said shell being provided with a pluralityof longitudinally extending members which are attached thereto, saidmembers being adapted to engage slabs of wood being debarked and to aidin imparting a tumbling action thereto, means for rotating said shellabout its longitudinal axis, the interior of said shell being interlacedwith a plurality of chains which are attached at each end to theinterior of said shell and which are adapted to break apartinterentangled pieces of wood being barked, and stationary meansoverlying the entire longitudinal extent of the path traveled by each ofsaid openings and in close proximity to the outer surface of saidcylinder for shearing oif any material which extends through saidopenings.

References Cited in the file of this patent UNITED STATES PATENTS1,247,526 Guettler n Nov. 20, 1917 1,324,193 Guettler Dec. 9, 19191,974,493 Hellner l l Sept. 25, 1934 2,599,090 Clark et a1. June 3, 19522,712,330 Thompson July 5, 1955 FOREIGN PATENTS 52,015 Norway Jan. 16,1933 85,739 Norway June 20, 1955

